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    <title>CSS边框动画</title>
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<body>
    <div class="zigzag">
        <div style="--i:0;"><span><b>C</b></span></div>
        <div style="--i:1;"><span><b>S</b></span></div>
        <div style="--i:2;"><span><b>S</b></span></div>
        <div style="--i:3;"><span><b>❤</b></span></div>
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        <div style="--i:1;"></div>
        <div style="--i:2;"></div>
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